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DESARROLLO Y VALIDACIóN DEL MODELADO DINáMICO PARA UNA CADENA CINEMáTICA CERRADA MEDIANTE TéCNICAS SIMBóLICAS Y NUMéRICAS
FRANCISCO VALERO C.,LUZ ADRIANA MEJíA C.
Scientia Et Technica , 2008,
Abstract: Mediante procedimientos simbólicos, en este artículo se desarrollan dos modelos dinámicos de la cadena cinemática cerrada para un cuarto de vehículo-robot. La validación del modelo se realiza por comparación con los resultados derivados del modelado mediante el software de simulación multicuerpo Adams.
Incremento de Interleucina-1 beta, Interferon gamma y Factor de Necrosis Tumoral alfa en suero y cerebro de ratones infectados con el virus de Encefalitis Equina Venezolana. Increase of Interleukin-1 Beta, Gamma Interferon and Tumor Necrosis Factor Alpha in serum and brain of mice infected with the Venezuelan Equine Encephalitis virus.
Nereida Valero,Ernesto Bonilla,Luz Marina Espina,Mery Maldonado
Investigación Clínica , 2008,
Abstract: Diversos esfuerzos han sido dirigidos a fin de esclarecer los principales mecanismos de protección y recuperación en las infecciones virales agudas y el posible papel de las citocinas involucradas en la respuesta inmunitaria primaria inducida por una cepa epizoótica del virus de Encefalitis Equina Venezolana (EEV). En el presente estudio se determinaron las concentraciones de citocinas TH1 Interleucina-2 (IL-2) e Interferon-gamma (IFN-g), TH2 Interleucina-4 (IL-4), proinflamatorias (IL-1b) y el Factor de Necrosis Tumoral -alfa (TNF-a) en suero y cerebro de ratones infectados con el virus de EEV a diferentes períodos de infección. Se utilizaron ratones NMRI albinos machos infectados con una suspensión (10 DL50) de la cepa Guajira del virus de EEV, y un grupo control (sin infectar). En los días 1, 3 y 5post-infección, se extrajo sangre completa de ratones para la obtención de suero y el cerebro previa perfusión, para la obtención de homogeneizados cerebrales. En ambas muestras se determinaron IL-2, IFN-g, IL-4, IL-1b, y TNF-a por la técnica de ELISA. Se observó un incremento significativo (p < 0,01) en suero y homogeneizados cerebrales al 1er, 3er y 5to día post-infección en las concentraciones de IL-1b, IFN-g y TNF-a, al compararlos con el grupo control. La cuantificación de IL-2 e IL-4, no arrojaron diferencias estadísticamente significativas al ser comparados con los controles. Estos resultados sugieren que la IL-1b, IFN-g y TNF-a, podrían estar involucradas en la respuesta inmunitaria temprana al virus de EEV durante la infección primaria. Considerable efforts have been directed to clarify the main protective and recovery mechanisms in acute viral infections and, the possible role of the cytokines involved in the primary immune response induced by an epizootic strain of the Venezuelan Equine Encephalitis (VEE) virus. This study examined the levels of TH1 cytokines Interleukin-2 (IL-2) and Interferon-gamma (IFN-g), TH2 cytokines Interleukin-4 (IL-4) and proinflammatory cytokines (IL-1b, TNF-a) in serum and brain of mice infected with the VEE virus during different post infection periods. NMRI albino male mice infected with a suspension (10 DL50) of the Guajira strain of the VEE virus, and a control group (without infection) were used. At one, 3 and 5 days post-infection, whole blood and brains were extracted to obtain sera and brain homogenates, respectively. IL-2, IFN-g, IL-4, IL-1b and TNF-a were determined by ELISA. A significant increment in the levels of IL-1b, IFN-g and TNF-a was observed (p<0.01) in serum and brain homogenates at 1, 3 and 5 day
Ultrastructural studies on dengue virus type 2 infection of cultured human monocytes
Jesus A Mosquera, Juan Hernandez, Nereida Valero, Luz Espina, German J A?ez
Virology Journal , 2005, DOI: 10.1186/1743-422x-2-26
Abstract: Typical dengue particles and fuzzy coated viral particles were 35 to 42 nm and 74 to 85 nm respectively. Viruses were engulfed by phagocytosis and macropicnocytosis leading to huge vacuoles and phagosomes inside the monocytes. Interaction of monocytes with DEN2 virus induced apoptosis, characterized by nuclear condensation and fragmentation, cellular shrinkage, blebbing and budding phenomena and phagocytosis of apoptotic cells by neighboring monocytes. This finding was confirmed by TUNEL. Ultrastructural features associated to DEN2 virus replication were not observed.These data suggest that clearance of the virus by monocytes and cellular death are the main features during the initial interaction of DEN2 virus and monocytes and this could be important in the rapid elimination of the virus after infection by mosquito vector.Monocyte/macrophages are one of the major target of dengue virus and responsible for virus dissemination after its initial entry via the mosquito vector [1-3]. A detailed study of this early virus-monocyte interaction by electron microscopy has not been performed. Since ultrastructural study is one of the important analysis in the interaction virus-cell, we performed electron microscopy studies in DEN2 virus- infected human monocytes at 1, 2, 4 and 6 hours of culture, in order to get more information regarding to morphological aspects of virus, virus replication, cellular alterations and apoptosis.After 1 hour of culture numerous virus particles were observed attached to plasma membrane, free in the extracellular space and in cytoplasmic vacuoles inside monocytes. The predominant viral particles in infected monocyte cultures were typical viral particles of 35 to 42 nm in diameter (Figures 1A, 1B, 1C). Small number of fuzzy coated viral particles (74 to 85 nm) showed a core similar to the usual dengue particles, but they had an envelope with projections, looking like a fuzzy coat (Figures 1D, 1E). Typical DEN2 virus particles observed in this study
Evaluación de la Inmunidad Contra los Virus de Encefalitis Equina Venezolana y Dengue en la Población Humana de San Carlos, Municipio Insular Almirante Padilla, Estado Zulia, Venezuela. A?o 1996
Valero,Nereida; A?ez,Florencio; Larreal,Yraima; Arias,Julia; Rodríguez,Zulay; Espina,Luz Marina;
Investigación Clínica , 2001,
Abstract: the insular municipality of almirante padilla, historically, has been affected by venezuelan equine encephalitis (vee) epidemics, that have occurred cyclically in the paez, mara and almirante padilla municipalities of the state of zulia. during the last epidemic outbreak (1995), the studies reported a great number of cases of vee in humans, based on epidemiologic-clinical diagnosis; occupying this municipality, the first place in the attack rate by the virus. at the same time, dengue has been defined as an endemic illness affecting different regions, whose etiologic agent has previously circulated in the studied zone. in order to evaluate the immunity acquired against these viruses, a serological study was conducted in san carlos island. two hundred and ten blood samples were obtained at random, among individuals of an age range between < 1 and 69 years, with and without antecedents of viral illness symptomatology at the moment of the epidemic outbreak, occurred in 1995. the samples were classified according to sex and age, and analyzed through the test of elisa for specific igg antibodies against the vee and dengue viruses. from the total of the samples processed, 116 (55,2 %) were positive for vee, affecting uniformly all age - groups with a slight masculine predominance. likewise, 88 cases (41,9 %) were determined positive for dengue virus, affecting mainly the group ranging from 10 to 19 years. these results let us suggest that the epidemic outbreak occurred in 1995 at the almirante padilla insular municipality, had a double nature with both viruses being involved in the etiology of febrile cases.
Capacidad Larvívora del Gold Fish (Carassius auratus auratus) y del Guppy Salvaje (Poecilia reticulata) Sobre Larvas de Aedes aegypti en Condiciones de Laboratorio
Valero,Nereida; Meleán,Eddy; Maldonado,Mery; Montiel,Milagros; Larreal,Yraima; Espina,Luz Marina;
Revista Científica , 2006,
Abstract: the biological control of vectors of medical importance is presented as an alternative to the use of plaguicides. the utilization of larvivorous fishes is promoted as a new strategy for the control of vectors. the proposal of this study is to evaluate the potential of two species of fishes for the biological control of mosquitoes aedes aegypti (main vector of dengue) under laboratory conditions. a growing number of larvaes in stages i, ii and iii of a. aegypti (n: 25, 50 and 100) was placed in aquariums with goldfish (carassius auratus auratus) and wild guppys (poecilia reticulata). the ratio body weight/eliminated larvaes/hour was quantified in ten assays. the species poecilia reticulata had a higher (p < 0.001) larvivorous capacity than the species c. auratus auratus, since when 25, 50 and 100 larvaes were administrated the poecilia reticulata were able to reach an average of larval elimination of 3.15 ± 0.12; 5.50 ± 0.31 and 10.95 ± 0.25, while the c. auratus auratus reached a maximum of 1.21 ± 0.03; 2.45 ± 0.02 and 4.73 ± 0.06. the results are indicative that under these conditions, both species of fish possess high capacity of elimination of larvaes of a. aegypti; however, considering their larvivorous capacity, readiness, cost, reproductive characteristics and resistance to the climatic conditions, the species poecilia reticulata offers important advantages over c. auratus auratus when both species are evaluated integrally as candidates for the biological control.
LOS PROBLEMAS DE SALUD RELACIONADOS CON EL AGUA DE CONSUMO
Richard J. Coronado,Luz Valero,Elizabeth M. Pérez Pérez
Salud, Arte y Cuidado , 2009,
Abstract: Due the importance of water sources and its ecological and social impact, it was decided to make a diagnosishealth problems related to water of consumption in Llanitos de Tabay, Sector Vista Alegre (Mérida, Venezuela), in orderto establish any relation between health problems presented by the inhabitants of this community and the resourceconsumption water. The study was performed means the application of surveys related to the topics before mentioned to50% of the population of the study sector. In addition, with the aim to relate the data contributed by the communityconcerning to diseases related to the quality of consumption waters, were obteined the morbidity data of year 2007 to theAmbolutorio Rural II de Tabay, which were correlated with the information contributed by the community. In agreementwith the realized surveys, the inhabitants report the existence of public health problems related to consumption water,being most important: amibiasis, diarrheas, escabiosis and parasitism. Secondly, according to morbidity data ofAmbulatory, the diseases reported by the community represent serious public health problems related to the quality ofconsumption water. Finally, according to the inhabitants of the sector in study, the problems related to the water could besolved implementing plans of waters treatment and with a major participation of public organisms
Inmunidad a flavivirus en la población indígena de la Sierra de Perijá, estado Zulia, Venezuela Immunity to flavivirus in amerindian population of the Sierra de Perijá, Zulia state, Venezuela
Nereida Valero,Luz Marina Espina,Jesús Estévez,Eddy Meleán
Investigación Clínica , 2004,
Abstract: Existe poca información acerca de la infección por Flavivirus en poblados amerindios del occidente de Venezuela, razón por la cual se determinó la actividad y seroprevalencia de los mismos y se analizó la hipótesis que sustenta la existencia de un ciclo selvático de transmisión de estas infecciones en poblaciones indígenas. Para ello, se recolectaron muestras de sangre en comunidades Yukpas (n = 144) y Barí (n = 110). De ellas, 35 muestras (Yukpas = 25 y Barí = 10) fueron procesadas por aislamiento en cultivo celular e identificación viral por RT-PCR. La determinación de anticuerpos IgG anti-Flavivirus se realizó a través de la técnica de ELISA. Los resultados obtenidos no evidenciaron casos activos de dengue y la seroprevalencia para IgG anti-Flavivirus en la población Yukpa fue significativamente mayor (p < 0,0001) que en la población Barí (43,1 vs 6,4%), evidenciándose inmunidad anti-Flavivirus en ambas poblaciones indígenas. Estos resultados muestran la existencia de una mayor seroprevalencia de Flavivirus en los Yukpas que en los Barí, lo cual sugiere una actividad contínua de estos virus, principalmente en la población Yukpa. Sin embargo, en estas poblaciones las causas o factores que condicionan la presencia o llegada de casos son variadas y, posiblemente, están relacionadas con la estructura de los poblados y los hábitos de intercambio social. No se evidenció característica alguna que apoyara la presencia de un ciclo selvático en la transmisión de estos virus, especialmente del dengue, en esta población. Little information is available about Flavivirus infection in amerindian populations in western Venezuela. On this account the activity and seroprevalence of these viruses were determined and the hypothesis concerning the existence of a sylvatic cycle, conditioning the infection transmission of these viruses in indigenous populations, was studied. For this, blood samples from Yukpas (n=144) and Barí (n=110) communities were collected, 35 (Yukpas = 25 y Barí =10) of which were processed for viral isolation followed by RT-PCR. The anti-Flavivirus IgG antibodies were determined by ELISA. The results did not show active Dengue cases and the seroprevalence of anti-Flavivirus IgG in the Yukpa population was significantly higher (p < 0,0001) than in the Bari population (43,1% vs. 6,4%). The present study has determined the presence of Flavivirus immunity in Yukpa and Barí populations. These results show a higher prevalence at the former than in the Bari population, which suggests circulation of Flavivirus, mainly in the Yukpa communities, being scarce
Caracterización fenotípica de especies de Malassezia en piel sana de población estudiantil universitaria
Rodríguez-Valero,Sofía; Mesa,Luz Mila; Gonzalez-Morán,Evelyn; Delmonte,María Lucía; Robertiz,Sandra; Valero,Alejandro;
Investigación Clínica , 2005,
Abstract: the yeasts of the malassezia genus are part of the normal skin of man and other vertebrates. the description of new species for this genus has induced on their study in several countries. for this reason, is important to do research in order to get epidemiologic data about malassezia species in tropical countries like venezuela, where the new malassezia species have not been reported this study was made on healthy skin of a university student population. the samples were taken from different body areas and inoculated in dixon modified medium and sabouraud dextrose agar medium e incubated at 32°c. the identification was achieved following the key of species described by gueho et al. and the tween diffusion test proposed by guillot et al. in this investigation the isolated specie was m. furfur, corresponding the major positive percentage to the age group from 16 to 20 years old (66.7%). the presence of malassezia was predominant on shoulder and chest (33.3% and 26.6%). there were not found significant differences between the evaluated groups, as was demonstrated by the applied statistical tests, exact fisher?s test and chi square test. it is important to continue the investigations on other age groups, in order to establish the prevalent species in our region and evaluate their pathogenic potential
Phosphorylation of AIB1 at Mitosis Is Regulated by CDK1/CYCLIN B
Macarena Ferrero, Juan Ferragud, Leonardo Orlando, Luz Valero, Manuel Sánchez del Pino, Rosa Farràs, Jaime Font de Mora
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0028602
Abstract: Background Although the AIB1 oncogene has an important role during the early phase of the cell cycle as a coactivator of E2F1, little is known about its function during mitosis. Methodology/Principal Findings Mitotic cells isolated by nocodazole treatment as well as by shake-off revealed a post-translational modification occurring in AIB1 specifically during mitosis. This modification was sensitive to the treatment with phosphatase, suggesting its modification by phosphorylation. Using specific inhibitors and in vitro kinase assays we demonstrate that AIB1 is phosphorylated on Ser728 and Ser867 by Cdk1/cyclin B at the onset of mitosis and remains phosphorylated until exit from M phase. Differences in the sensitivity to phosphatase inhibitors suggest that PP1 mediates dephosphorylation of AIB1 at the end of mitosis. The phosphorylation of AIB1 during mitosis was not associated with ubiquitylation or degradation, as confirmed by western blotting and flow cytometry analysis. In addition, luciferase reporter assays showed that this phosphorylation did not alter the transcriptional properties of AIB1. Importantly, fluorescence microscopy and sub-cellular fractionation showed that AIB1 phosphorylation correlated with the exclusion from the condensed chromatin, thus preventing access to the promoters of AIB1-dependent genes. Phospho-specific antibodies developed against Ser728 further demonstrated the presence of phosphorylated AIB1 only in mitotic cells where it was localized preferentially in the periphery of the cell. Conclusions Collectively, our results describe a new mechanism for the regulation of AIB1 during mitosis, whereby phosphorylation of AIB1 by Cdk1 correlates with the subcellular redistribution of AIB1 from a chromatin-associated state in interphase to a more peripheral localization during mitosis. At the exit of mitosis, AIB1 is dephosphorylated, presumably by PP1. This exclusion from chromatin during mitosis may represent a mechanism for governing the transcriptional activity of AIB1.
Etiología viral de las infecciones respiratorias agudas
Valero,Nereida; Larreal,Yraima; Arocha,Francisco; Gotera,Jennifer; Mavarez,Alibeth; Bermudez,John; Moran,Maria; Maldonado,Merybell; Espina,Luz Marina;
Investigación Clínica , 2009,
Abstract: acute respiratory infections (ari) are pathologies that affect the respiratory tract from the proximal pharynx to the lungs, with an evolution of less than 15 days. they constitute the most frequent cause of morbimortality in the world. with the purpose of identifying the viral agents associated to this type of infections in patients of zulia state, venezuela, between february 2005 and july 2006, a total of 102 samples of the respiratory tract (oropharyngeal swab, nasopharyngeal swab, nasopharyngeal washing, spit and bronchoalveolar lavage) were studied. viral isolation was made through a cellular culture and the identification of the pathogenic agents by the technique of direct immunofluorescence. forty six positive samples were obtained (45%). the greater incidence was found in the groups of 41 to 64 years old patients, followed by lactanting babies (1 to 23 months). there were no significant differences between sexes. within the isolated viral pathogens, respiratory syncytial virus (rsv) was the agent most frequently found (32.6% p<0.05), followed by adenovirus (28.2%), parainfluenza (23.9%) and influenza (15.2%). the respiratory infections of the low respiratory tract were the most frequent (67.4%). a high incidence of associated viral agents to ari in zulia state is demonstrated. a high incidence in adult patients and the greatest positivity was found for rsv.
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